Intercalates; exfoliates; process for manufacturing intercalates and exfoliates and composite materials containing same

ABSTRACT

Intercalates formed by mixing the phyllosilicate with a polymer and a liquid carrier, and extruding the mixture through a die-opening to adsorb or intercalate the polymer between adjacent phyllosilicate platelets. Sufficient polymer is adsorbed between adjacent phyllosilicate platelets to expand the adjacent platelets to a spacing of at least about 10 Å (as measured after water removal), up to about 55 Å and preferably in the range of about 30-40 Å, so that the intercalate easily can be exfoliated into individual platelets by heating the polymer to its melting point, to provide a matrix polymer/platelet composite material.

FIELD OF THE INVENTION

The present invention is directed to intercalated layered materials, andexfoliates thereof, manufactured by sorption (adsorption and/orabsorption) of one or more oligomers or polymers between planar layersof a swellable layered material, such as a phyllosilicate or otherlayered material, to expand the interlayer spacing of adjacent layers toat least about 10 Å. More particularly, the present invention isdirected to intercalates having at least two layers of oligomer and/orpolymer molecules sorbed on the internal surfaces of adjacent layers ofthe planar platelets of a layered material, such as a phyllosilicate,preferably a smectite clay. The intercalates are formed by contactingthe layered material with a polymer and a liquid carrier, the liquidcarrier being admixed with the layered material and the polymer in anamount of carrier in the range of about 10% to about 80% carrier, basedon the dry weight of the layered material, preferably water, to expandthe interlayer spacing to at least about 10 Angstroms, preferably to atleast about 20 Angstroms, and more preferably to at least about 30-45Angstroms, up to about 100 Å, or disappearance of periodicity. Theresulting intercalates are neither entirely organophilic nor entirelyhydrophilic, but a combination of the two, and easily can be exfoliatedfor or during admixture with a thermoplastic or thermosetting matrixpolymer melt, preferably a thermoplastic matrix polymer, to improve oneor more properties of the matrix polymer. The resulting matrixpolymer/platelet composite materials are useful wherever polymer/fillercomposite materials are used, for example, as external body parts forthe automotive industry; heat-resistant polymeric automotive parts incontact with an engine block; tire cord for radial tires; food wraphaving improved gas impermeability; electric components; food gradedrink containers; and any other use where it is desired to alter one ormore physical properties of a matrix polymer, such as elasticity andtemperature characteristics, e.g., glass transition temperature and hightemperature resistance.

BACKGROUND OF THE INVENTION AND PRIOR ART

It is well known that phyllosilicates, such as smectite clays, e.g.,sodium montmorillonite and calcium montmorillonite, can be treated withorganic molecules, such as organic ammonium ions, to intercalate theorganic molecules between adjacent, planar silicate layers, therebysubstantially increasing the interlayer (interlaminar) spacing betweenthe adjacent silicate layers. The thus-treated, intercalatedphyllosilicates, having interlayer spacing of at least about 10-20Angstroms and up to about 100 Angstroms, then can be exfoliated, e.g.,the silicate layers are separated, e.g., mechanically, by high shearmixing. The individual silicate layers, when admixed with a matrixpolymer, before, after or during the polymerization of the matrixpolymer, e.g., a polyamide--see U.S. Pat. Nos. 4,739,007; 4,810,734; and5,385,776--have been found to substantially improve one or moreproperties of the polymer, such as mechanical strength and/or hightemperature characteristics.

Exemplary of such prior art composites, also called "nanocomposites",are disclosed in published PCT disclosure of Allied Signal, Inc. WO93/04118 and U.S. Pat. No. 5,385,776, disclosing the admixture ofindividual platelet particles derived from intercalated layered silicatematerials, with a polymer to form a polymer matrix having one or moreproperties of the matrix polymer improved by the addition of theexfoliated intercalate. As disclosed in WO 93/04118, the intercalate isformed (the interlayer spacing between adjacent silicate platelets isincreased) by adsorption of a silane coupling agent or an onium cation,such as a quaternary ammonium compound, having a reactive group which iscompatible with the matrix polymer. Such quaternary ammonium cations arewell known to convert a highly hydrophilic clay, such as sodium orcalcium montmorillonite, into an organophilic clay capable of sorbingorganic molecules. A publication that discloses direct intercalation(without solvent) of polystyrene and poly(ethylene oxide) in organicallymodified silicates is Synthesis and Properties of Two-DimensionalNanostructures by Direct Intercalation of Polymer Melts in LayeredSilicates, Richard A. Vaia, et al., Chem. Mater., 5:1694-1696(1993).Also as disclosed in Adv. Materials, 7, No. 2: (1985), pp, 154-156, NewPolymer Electrolyte Nanocomposites: Melt Intercalation of Poly(EthyleneOxide) in Mica-Type Silicates, Richard A. Vaia, et al., poly(ethyleneoxide) can be intercalated directly into Na-montmorillonite andLi-montmorillonite by heating to 80° C. for 2-6 hours to achieve ad-spacing of 17.7 Å. The intercalation is accompanied by displacingwater molecules, disposed between the clay platelets with polymermolecules. Apparently, however, the intercalated material could not beexfoliated and was tested in pellet form. It was quite surprising to oneof the authors of these articles that exfoliated material could bemanufactured in accordance with the present invention.

Previous attempts have been made to intercalate polyvinylpyrrolidone(PVP), polyvinyl alcohol (PVA) and poly(ethylene oxide) (PEO) betweenmontmorillonite clay platelets with little success. As described inLevy, et al., Interlayer Adsorption of Polyvinylpyrrolidone onMontmorillonite, Journal of Colloid and Interface Science, Vol. 50, No.3, March 1975, pages 442-450, attempts were made to sorb PVP (40,000average M.W.) between monoionic montmorillonite clay platelets (Na, K,Ca and Mg) by successive washes with absolute ethanol, and thenattempting to sorb the PVP by contact with 1% PVP/ethanol/watersolutions, with varying amounts of water, via replacing the ethanolsolvent molecules that were sorbed in washing (to expand the plateletsto about 17.7 Å). Only the sodium montmorillonite had expanded beyond a20 Å0 basal spacing (e.g., 26 Å and 32 Å), at 5⁺ % H₂ O, after contactwith the PVP/ethanol/H₂ O solution. It was concluded that the ethanolwas needed to initially increase the basal spacing for later sorption ofPVP, and that water did not directly affect the sorption of PVP betweenthe clay platelets(Table II, page 445), except for sodiummontmorillonite. The sorption was time consuming and difficult and metwith little success.

Further, as described in Greenland, Adsorption of Polyvinyl Alcohols byMontmorillonite, Journal of Colloid Sciences, Vol. 18, pages 647-664(1963), polyvinyl alcohols containing 12% residual acetyl groups couldincrease the basal spacing by only about 10 Å due to the sorbedpolyvinyl alcohol (PVOH). As the concentration of polymer in theintercalant polymer-containing solution was increased from 0.25% to 4%,the amount of polymer sorbed was substantially reduced, indicating thatsorption might only be effective at polymer concentrations in theintercalant polymer-containing composition on the order of 1% by weightpolymer, or less. Such a dilute process for intercalation of polymerinto layered materials would be exceptionally costly in drying theintercalated layered materials for separation of intercalate from thepolymer carrier, e.g., water, and, therefore, apparently no further workwas accomplished toward commercialization.

In accordance with one embodiment of the present invention, intercalatesare prepared by contacting a phyllosilicate with a PVP polymer,preferably essentially alcohol-free, or a PVA intercalant polymercomposition, wherein the PVA preferably contains 5% or less residualacetyl groups, more preferably fully hydrolyzed, containing 1% or lessacetyl groups.

In accordance with an important feature of the present invention, bestresults are achieved using an oligomer (herein defined as a pre-polymerhaving 2 to about 15 recurring monomeric units, which can be the same ordifferent) or polymer (herein defined as having more than about 15recurring monomeric units, which can be the same or different)composition for intercalation having-at least about 2%, preferably atleast about 5% by weight intercalant oligomer or intercalant polymerconcentration, more preferably about 50% to about 80% by weight oligomerand/or polymer, based on the weight of oligomer and/or polymer andcarrier (e.g., water and/or other solvent for the intercalant oligomeror intercalant polymer) to achieve better sorption of the intercalantpolymers between phyllosilicate platelets and so that less drying isrequired after intercalation. The oligomer or polymer sorbed betweensilicate platelets that causes separation or added spacing betweenadjacent silicate platelets and, for simplicity of description, both theoligomers and polymers are hereinafter called the "intercalant" or"intercalant polymer" or "polymer intercalant". In this manner, thewater-soluble oligomers or polymers will be sorbed sufficiently toincrease the interlayer spacing of the phyllosilicate in the range ofabout 10 Å to about 100 Å, for easier and more complete exfoliation, ina commercially viable process, regardless of the particularphyllosilicate or intercalant polymer.

In accordance with the present invention, it has been found that aphyllosilicate, such as a smectite clay, can be intercalatedsufficiently for subsequent exfoliation by sorption of polymers oroligomers that have carbonyl, hydroxyl, carboxyl, amine, amide, and/orether functionalities, or aromatic rings to provide metal cationchelate-type bonding between two functional groups of one or twointercalant polymer molecules and the metal cations bonded to the innersurfaces of the phyllosilicate platelets. Sorption and metal cationelectrostatic attraction or bonding of a platelet metal cation betweentwo oxygen or nitrogen atoms of the molecules; or the electrostaticbonding between the interlayer cations in hexagonal or pseudohexagonalrings of the smectite layers and an intercalant polymer aromatic ringstructure increases the interlayer spacing between adjacent silicateplatelets or other layered material to at least about 10 Å, andpreferably at least about 20 Å, and more preferably in the range ofabout 30 Å to about 45 Å. Such intercalated phyllosilicates easily canbe exfoliated into individual phyllosilicate platelets before or duringadmixture with a thermoplastic or thermosetting matrix polymer to form amatrix polymer/platelet composite material, or nanocomposite, having oneor more properties substantially improved in comparison with the matrixpolymer alone.

To achieve the full advantage of the present invention, the intercalantpolymer should be intimately mixed with the phyllosilicate using aminimum amount of carrier, such as water and/or alcohol, to minimize theexpense in drying the intercalate. It has been found that by dry mixingparticles of solid intercalant polymer with dry particulatephyllosilicate layered material, adding about 10% to about 90% water,preferably about 20% to about 50% water, based on the dry weight of thephyllosilicate, and intimately mixing, e.g., by extruding the mixture,the phyllosilicate is efficiently intercalated, easily dried, andexfoliated.

Such intercalated phyllosilicates easily can be exfoliated before orduring admixture with a thermoplastic or thermosetting matrix polymer toexfoliate the intercalate into individual phyllosilicate platelets, andform a matrix polymer/platelet composite material, or nanocomposite,having one or more properties substantially improved in comparison withthe matrix polymer alone.

DEFINITIONS

Whenever used in this Specification, the terms set forth shall have thefollowing meanings:

"Layered Material" shall mean an inorganic material, such as a smectiteclay mineral, that is in the form of a plurality of adjacent, boundlayers and has a maximum thickness, for each layer, of about 100 Å.

"Platelets" shall mean individual layers of the Layered Material.

"Intercalate" or "Intercalated" shall mean a Layered Material thatincludes oligomer and/or polymer molecules disposed between adjacentplatelets of the Layered Material to increase the interlayer spacingbetween the adjacent platelets to at least 10 Å.

"Intercalation" shall mean a process for forming an Intercalate.

"Exfoliate" or "Exfoliated" shall mean individual platelets of anIntercalated Layered Material so that adjacent platelets of theIntercalated Layered Material can be dispersed individually throughout acarrier material, such as a matrix polymer.

"Exfoliation" shall mean a process for forming an Exfoliate from anIntercalate.

"Nanocomposite" shall mean an oligomer, polymer or copolymer havingdispersed therein a plurality of individual platelets obtained from anExfoliated, Intercalated Layered Material.

"Matrix Polymer" shall mean a thermoplastic or thermosetting polymer inwhich the Exfoliate is dispersed to form a Nanocomposite.

"Intercalant Polymer" or "Intercalant" shall mean an ologimer or polymerthat is sorbed between Platelets of the Layered Material to form anIntercalant.

SUMMARY OF THE INVENTION

In brief, the present invention is directed to intercalates formed bycontacting a layered phyllosilicate with an organic monomer, an oligomerand/or polymer to sorb or intercalate the intercalant polymer ormixtures of intercalant polymers between adjacent phyllosilicateplatelets. Sufficient intercalant polymer is sorbed between adjacentphyllosilicate platelets to expand the spacing between adjacentplatelets (interlayer spacing) to a distance of at least about 10 Å (asmeasured after water removal) and preferably in the range of about 30-45Å, so that the intercalate easily can be exfoliated, sometimesnaturally, without shearing being necessary. At times, the intercalaterequires shearing that easily can be accomplished, e.g., when mixing theintercalate with a polymer melt, to provide a matrix polymer/plateletcomposite material or nanocomposite--the platelets being obtained byexfoliation of the intercalated phyllosilicate.

The intercalant polymer should have an affinity for the phyllosilicateso that it is sorbed between, and is maintained associated with thesilicate platelets in the interlayer spaces, and after exfoliation. Inaccordance with the present invention, the intercalant polymer can bewater-soluble, water-dispersible, or water-insoluble so long as thepolymer includes an aromatic ring and/or has a functionality selectedfrom the group consisting of a carbonyl; carboxyl; hydroxyl; amine;amide; ether; and ester structures. Polymers having at least one ofthese functionalities are sufficiently bound to an inner surface of thephyllosilicate platelets (it is hereby theorized, by metal cationelectrostatic bonding or complexing, e.g., chelation, of at least onemetal cation on the inner surface of the phyllosilicate platelet sharingelectrons with two carbonyl, two carboxyl, two oxygen; two hydroxyl, twoamine and/or two amide functionalities of one intercalant polymermolecule, or of two adjacent intercalant polymer molecules). Suchintercalant polymers have sufficient affinity for the phyllosilicateplatelets to maintain sufficient interlayer spacing for exfoliation,without the need for coupling agents or spacing agents, such as theonium ion or silane coupling agents disclosed in the above-mentionedprior art.

Sorption of an intercalant polymer should be sufficient to achieveexpansion of adjacent platelets of the layered material (when measureddry) to an interlayer spacing of at least about 10 Å, preferably aspacing of at least about 20 Å, and more preferably a spacing of about30-45 Å. To achieve intercalates that can be exfoliated easily using thepolymer intercalants disclosed herein, the concentration of intercalantpolymer in an intercalant polymer-containing composition contacting thephyllosilicate should be at least about 2% by weight, preferably atleast about 5%, more preferably at least about 15%, and most preferablyat least about 20% polymer, for example about 25% to about 100% byweight polymer, based on the weight of polymer plus carrier (organicsolvent for the polymer, e.g., methanol or ethanol; and/or water).

It has been found that the intercalates of the present invention areincreased in interlayer spacing step-wise. If the phyllosilicate iscontacted with an intercalant polymer-containing composition containingless than about 16% by weight polymer, e.g., 10% to about 15% by weightpolymer, based on the dry weight of the phyllosilicate, a monolayerwidth of polymer is sorbed (intercalated) between the adjacent plateletsof the layered material. A monolayer thickness of polymer betweenplatelets has been found to increase the interlayer spacing to less than10 Å. When the amount of intercalant polymer is in the range of about16% to less than about 35% by weight, based on the weight of the drylayered material, the intercalant polymer is sorbed in a bilayer,thereby increasing the interlayer spacing to about 10 Å to about 16 Å.At an intercalant polymer loading in the intercalant-containingcomposition of about 35% to less than about 55% intercalant polymer,based on the dry weight of the layered material contacted, theinterlayer spacing is increased to about 20 Å to about 25 Å,corresponding to three layers of intercalant polymer sorbed betweenadjacent platelets of the layered material. At an intercalant polymerloading of about 55% to about 80% intercalant polymer, based on the dryweight of the layered material dissolved or dispersed in the intercalantpolymer-containing composition, the interlayer spacing will be increasedto about 30 Å to about 35 Å, corresponding to 4 and 5 layers ofintercalant polymer sorbed (intercalated) between adjacent platelets ofthe layered material, as shown in FIGS. 1 and 2.

Such interlayer spacings have never been achieved by directintercalation of an oligomer or polymer molecule, without prior sorptionof a swelling agent, such as an onium or silane coupling agent, andprovides easier and more complete exfoliation for or duringincorporation of the platelets into a thermoplastic or thermosettingmatrix polymer. Such intercalates are especially useful in admixturewith matrix thermoplastic or thermosetting polymers in the manufactureof polymeric articles from the polymer/platelet composite materials; andfor admixture of the intercalates and exfoliated intercalates with polarsolvents in modifying rheology, e.g., of cosmetics, oil-well drillingfluids, in the manufacture of oil and grease, and the like.

Once exfoliated, the platelets of the intercalate are predominantlycompletely separated into individual platelets and the originallyadjacent platelets no longer are retained in a parallel, spaceddisposition, but are free to move as predominantly individual plateletsthroughout a matrix polymer melt to act similar to a nanoscale fillermaterial for the matrix polymer. Once the polymer/platelet compositematerial is set and hardened into a desired shape, the predominantlyindividual phyllosilicate platelets are permanently fixed in positionand are randomly, homogeneously and uniformly dispersed, predominantlyas individual platelets, throughout the matrix polymer/plateletcomposite material.

As recognized, the thickness of the exfoliated, individual platelets(about 10 Å) is relatively small compared to the size of the flatopposite platelet faces. The platelets have an aspect ratio in the rangeof about 200 to about 2,000. Dispersing such finely divided plateletparticles into a polymer melt imparts a very large area of contactbetween polymer and platelet particles, for a given volume of particlesin the composite, and a high degree of platelet homogeneity in thecomposite material. Platelet particles of high strength and modulus,dispersed at sub-micron size (nanoscale), impart greater mechanicalreinforcement and a higher glass transition temperature (Tg) to thepolymer matrix than do comparable loadings of conventional reinforcingfillers of micron size, and can impart lower permeability to matrixpolymers than do comparable loadings of conventional fillers.

While the nanocomposites disclosed in WO 93/04118 require aswelling/compatibilizing agent, such as a silane coupling agent, or aquaternary ammonium molecule, that has distinct bonding interactionswith both the polymer and the platelet particle to achieve improvedproperties in the polymer, the polymer intercalants used to form theintercalates and exfoliates in accordance with the present inventionneed not have any (but can include) reactivity with the matrix polymerin which the inventive intercalates and exfoliates are dispersed, whileimproving one or more properties of the matrix polymer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph plotting interlayer space for polyvinylpyrrolidone(PVP):smectite clay complexes (intercalates) showing d(001) and d(002)spacing, in Angstroms, between smectite clay platelets versus percentageof PVP sorbed, based on the dry weight of the smectite clay;

FIG. 2 is a graph plotting interlayer space for polyvinylalcohol(PVA):smectite clay complexes (intercalates) showing d(001) spacing, inAngstroms, between smectite clay platelets versus percentage of PVAsorbed, based on the dry weight of the smectite clay;

FIG. 3 is an x-ray diffraction pattern for a complex of PVP (weightaverage molecular weight of 10,000):sodium montmorillonite clay, inAngstroms, at a weight ratio of PVP:clay of 20:80;

FIG. 4 is an x-ray diffraction pattern for a complex of PVP (weightaverage molecular weight of 40,000):sodium montmorillonite clay, inAngstroms, at a weight ratio of PVP:clay of 20:80;

FIG. 5 is an x-ray diffraction pattern for a complex of PVA (weightaverage molecular weight of 15,000):sodium montmorillonite clay, inAngstroms, at a weight ratio of PVA:clay of 20:80;

FIG. 6 is an x-ray diffraction pattern for a complex of PVP:sodiummontmorillonite clay, in Angstroms, at a weight ratio of PVP:clay of20:80 (upper pattern); and an x-ray diffraction pattern for ≈100% sodiummontmorillonite clay having a crystobalite impurity (lower pattern);

FIG. 7 is an x-ray diffraction pattern for a complex of PVP:sodiummontmorillonite clay, in Angstroms, at a weight ratio of PVP:clay of50:50 (upper pattern); and an x-ray diffraction pattern for ≈100% sodiummontmorillonite clay having a crystobalite impurity (lower pattern);

FIG. 8 is a portion of an x-ray diffraction pattern for PVP:sodiummontmorillonite clay, in Angstroms, at a PVP:clay ratio of 80:20,showing a PVP:clay complex peak or d(001) spacing of about 41 Å;

FIG. 9 is an x-ray diffraction pattern for a mechanical blend of apolyamide and a dry (about 8% by weight moisture) sodium montmorilloniteclay in a weight ratio of 80 polyamide:20 sodium montmorillonite clay(upper pattern); and ≈100% sodium montmorillonite clay, with acrystobalite impurity, (lower pattern), showing characteristic smectiteclay d(001) peaks at about 12.4 Å, d(020) smectite clay peaks at about4.48 Å; and a crystobalite impurity peak at about 4.05 Å for both upperand lower patterns;

FIG. 10 is an x-ray diffraction pattern for the mechanical blend shownin the upper pattern (80 polyamide:20 sodium montmorillonite clay) ofFIG. 9, after heating the mechanical blend to the melt temperature ofthe polyamide (upper pattern) to achieve intercalation and exfoliation,in comparison to the x-ray diffraction pattern for ≈100% sodiummontmorillonite clay, having a crystobalite impurity, (lower pattern),showing the disappearance of the characteristic smectite clay d(001)peak at about 12.4 Å; the d(020) peak at about 4.48 Å, characteristic ofsingle smectite platelets; and a characteristic crystobalite impuritypeak at about 4.08 Å (upper pattern);

FIG. 11 is an x-ray diffraction pattern similar to FIG. 9, showing amechanical blend of dimethylterephthalate (DMTPh) (70% by weight) anddry (about 8% moisture) sodium montmorillonite clay (30% by weight), ona smaller scale than FIG. 9, showing a characteristic smectite clayd(001) peak at about 12.4 Å for the mechanical blend; and an x-raydiffraction pattern for 100% DMTPh;

FIG. 12 is an x-ray diffraction pattern for the 70:30 mechanical blendof DMTPh:clay shown in FIG. 11, after heating the blend to above themelt temperature of the DMTPh (about 230° C.), showing the disappearanceof the characteristic smectite clay d(001) peak (about 12.4 Å) for themelt, showing exfoliation, and a DMTPh:clay complex (intercalate) peakat about 12.5 Å; and an x-ray diffraction pattern for 100% DMTPh;

FIG. 13 is an x-ray diffraction pattern for a 230° C. melt (complex) ofpolyethyleneterephthalate (PET):sodium montmorillonite clay at a weightratio of PET:clay of 90:10 (upper pattern) showing the disappearance ofthe characteristic smectite d(001) peak at about 12.4 Å for the melt,showing exfoliation; and an x-ray diffraction pattern for ≈100% sodiumbentonite, having a crystobalite impurity, (lower pattern);

FIG. 14 is an x-ray diffraction pattern for a 250° C. melt (complex) ofhydroxyethylterephthalate (HETPh):sodium montmorillonite clay at aweight ratio of HETPh:clay of 60:40 (upper pattern) showing thedisappearance of the characteristic smectite d(001) peak at about 12.4 Åfor the melt, showing exfoliation; and an x-ray diffraction pattern for100% HETPh (lower pattern);

FIG. 15 is an x-ray diffraction pattern for 250° C. melt (complex) ofhydroxybutylterephthalate (HBTPh):sodium montmorillonite clay at aweight ratio of HBTPh:clay of 60:40 (upper pattern) showing thedisappearance of the characteristic smectite d(001) peak at about 12.4 Åfor the melt, showing exfoliation; and an x-ray diffraction pattern for100% HETPh (lower pattern); and

FIG. 16 is an x-ray diffraction pattern for a polycarbonate:sodiummontmorillonite clay complex at a melted blend (280° C.) ratio ofpolycarbonate:clay of 50:50, showing the disappearance of thecharacteristic smectite d(001) peak at about 12.4 Å for the melt,showing exfoliation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

To form the intercalated materials of the present invention, thephyllosilicate should be swelled or intercalated by sorption of awater-soluble or water-insoluble oligomer or polymer that includes anaromatic ring and/or a functionality selected from the group consistingof carbonyl; carboxyl; hydroxyl; amine; amide; ether; ester; orcombinations thereof. In accordance with a preferred embodiment of thepresent invention, the phyllosilicate should include at least 5% byweight water, based on the dry weight of the phyllosilicate, preferablyabout 7% to about 20% water, prior to or during contact with theintercalant polymer to achieve sufficient intercalation for exfoliation.The amount of intercalant polymer in contact with the phyllosilicatefrom the intercalant polymer-containing composition should provide anintercalant polymer/phyllosilicate weight ratio (based on the dry weightof the phyllosilicate) of at least about 10/100, preferably at leastabout 16/100, and more preferably about 20-70/100, to provide sufficientsorption (intercalation) of the water-soluble or water-insolubleoligomer or polymer between the platelets of the layered material, e.g.,phyllosilicate, for easy exfoliation of the intercalates, andcommercially viable drying times (preferably about 16 to about 70percent by weight intercalant polymer, based on the dry weight of thelayered silicate material).

The intercalant polymer carrier, e.g., water, and/or organic solvent,advantageously is kept to a minimum during the sorption (absorptionand/or adsorption) of intercalant polymer. In accordance with apreferred embodiment of the present invention, the phyllosilicate anddry polymer can be admixed and then water added to thephyllosilicate/polymer blend, in an amount of about 10% to about 90% byweight water, based on the dry weight of the phyllosilicate, preferablyabout 20% to about 50% by weight water. Optimum water addition has beenfound to be about 35% to about 40% by weight water, based on the dryweight of the phyllosilicate intercalated. In accordance with anotherimportant feature of the present invention, it has been found thephyllosilicate/polymer/carrier blend can be sufficiently and intimatelycontacted (blended) for effective intercalation simply by extruding amixture of the phyllosilicate, polymer, water and/or organic solvent ata moisture (H₂ O) or organic solvent content in the range of about 20%to about 80% by weight, preferably about 20% to about 50% H₂ O or otherliquid carrier, based on the dry weight of the phyllosilicate.

The polymer intercalants are blended with the phyllosilicate in the formof a solid or liquid composition (neat particulate polymer having aparticle size for easy solubilization or dispersion, i.e., 1 millimeteror less, or aqueous and/or with a solvent, e.g., hydroalcoholic)together with an intercalant polymer carrier, e.g., water, such that thecarrier concentration in the phyllosilicate/polymer/carrier blend is atleast about 10%, preferably about 20% to about 50% by weight water, morepreferably at a carrier concentration of about 35% to about 40% byweight, with about 40% to about 80% by weight intercalant polymer, basedon the dry weight of the phyllosilicate, for intercalant polymersorption. The polymer can be added as a solid, solution or dispersion inthe carrier with the addition to the layered material/polymer blend ofpreferably about 20% to about 50% water, or other solvent for theintercalant polymer, based on the dry weight of layered material, morepreferably about 35% to about 40% water or other carrier solvent, sothat less water or solvent is sorbed by the intercalate, therebynecessitating less drying energy after intercalation. The intercalantsmay be introduced into the spaces between every layer, nearly everylayer, or at least a predominance of the layers of the layered materialsuch that the subsequently exfoliated platelet particles are preferably,predominantly less than about 5 layers in thickness; more preferably,predominantly about 1 or 2 layers in thickness; and most preferably,predominantly single platelets.

Any swellable layered material that sufficiently sorbs the intercalantpolymer to increase the interlayer spacing between adjacentphyllosilicate platelets to at least about 10 Å (when the phyllosilicateis measured dry) may be used in the practice of this invention. Usefulswellable layered materials include phyllosilicates, such as smectiteclay minerals, e.g., montmorillonite, particularly sodiummontmorillonite; magnesium montmorillonite; and/or calciummontmorillonite; nontronite; beidellite; volkonskoite; hectorite;saponite; sauconite; sobockite; stevensite; svinfordite; vermiculite;and the like. Other useful layered materials include micaceous minerals,such as illite and mixed layered illite/smectite minerals, such asledikite and admixtures of illites with the clay minerals named above.

Other layered materials having little or no charge on the layers may beuseful in this invention provided they can be intercalated with theintercalant polymers to expand their interlayer spacing to at leastabout 10 Å. Preferred swellable layered materials are phyllosilicates ofthe 2:1 type having a negative charge on the layers ranging from about0.15 to about 0.9 charges per formula unit and a commensurate number ofexchangeable metal cations in the interlayer spaces. Most preferredlayered materials are smectite clay minerals such as montmorillonite,nontronite, beidellite, volkonskoite, hectorite, saponite, sauconite,sobockite, stevensite, and svinfordite.

As used herein the "interlayer spacing" refers to the distance betweenthe internal faces of the adjacent layers as they are assembled in thelayered material before delamination (exfoliation) takes place. Theinterlayer spacing is measured when the layered material is "air dry",e.g., contains 3-6% by weight water, based on the dry weight of thelayered material. The preferred clay materials generally includeinterlayer cations such as Na⁺, Ca⁺², K⁺, Mg⁺², NH₄ ⁺ and the like,including mixtures thereof. In this state, these materials do notdelaminate in host (matrix) polymer melts regardless of the degree ofshear used in mixing, because their interlayer spacings are usuallyequal to or less than about 4 Å; consequently the interlayer cohesiveforce is relatively strong.

The amount of intercalant polymer intercalated into the swellablelayered materials useful in this invention, in order that theintercalated layered material may be exfoliated or delaminated intoindividual platelets, may vary substantially between about 15% and about80%, based on the dry weight of the layered silicate material. In thepreferred embodiments of the invention, amounts of polymer intercalantsemployed, with respect to the dry weight of layered material beingintercalated, will preferably range from about 16 grams of intercalantpolymer/100 grams of layered material (dry basis) to about 80 gramsintercalant polymer/100 grams of layered material. More preferredamounts are from about 20 grams intercalant polymer/100 grams of layeredmaterial to about 60 grams intercalant polymer/100 grams of layeredmaterial (dry basis).

The polymer intercalants are introduced into (sorbed within) theinterlayer spaces of the layered material by any suitable method as, forexample, by contacting the phyllosilicate with a concentratedintercalant polymer or intercalant polymer/water solution, orintercalant polymer/organic solvent, e.g., ethanol solution. The carrier(preferably water and/or alcohol, e.g., ethanol) can be added by firstsolubilizing or dispersing the polymer in the carrier; or the drypolymer and dry phyllosilicate can be blended and the carrier added tothe blend, or to the phyllosilicate prior to adding the dry polymer. Inevery case, it has been found that surprising sorption of polymerbetween platelets is achieved at relatively low loadings of carrier,especially H₂ O, e.g., about 5% to about 50% water, based on the dryweight of polymer plus phyllosilicate. Alternatively, the carrier, e.g.,water, can be added directly to the phyllosilicate prior to adding theintercalant polymer, either dry or in solution. Sorption of the polymerintercalant molecules may be performed by exposing finely divided (e.g.,35 μm to 150 μm, preferably 50 μm to 100 μm) layered material to drypolymer intercalant, or to a solution of polymer intercalant and water,or other liquid carrier, such that the phyllosilicate/water mixturecontains at least about 10% by weight water, preferably about 20% toabout 50% water based on the dry weight of the layered material. Theblend then is intimately mixed, such as by mechanical mixing orextrusion, to achieve intercalation of polymer between platelets of thelayered material. Sorption may be aided by exposure of the mixture ofintercalant polymer, water, and layered material to heat, pressure,ultrasonic cavitation, or microwaves, but such aids are not necessary toachieve sufficient polymer intercalation for later exfoliation of theintercalates into individual platelets.

In accordance with one important embodiment of the present invention,one or more polymerizable monomers are intercalated between theplatelets of the layered material, or simply admixed with the exfoliatedlayered material, and the polymerizable monomer(s) are polymerized whileintercalated between platelets, or while in contact with the intercalateor exfoliated intercalate. The polymerizable monomer(s) can be, forexample, a mixture of a diamine and a dicarboxylic acid suitable forreaction to produce a polyamide, e.g., nylon, or any of thepolymerizable organic liquids, that polymerize to form polymers,disclosed in U.S. Pat. No. 4,251,576, hereby incorporated by reference.

The preferred polymer intercalants are water-soluble, such aspolyvinylpyrrolidone (PVP) having a monomeric structure (I) as follows:##STR1##

The water-solubility of PVP can be adjusted according to (1) the degreeof hydrolysis of the polyvinylpyrrolidone, and (2) by forming a metalsalt of PVP, such as sodium or potassium. PVP can be hydrolyzed to thestructure (II): ##STR2## and the PVP can be intercalated in the saltform, e.g., sodium or potassium polyvinylpyrrolidone. Preferred PVPintercalants, and the following PVP derivatives, should have a weightaverage molecular weight in the range of about 100 to about 100,000 ormore, more preferably about 1,000 to about 40,000.

Other suitable water-soluble vinyl polymers include poly(vinyl alcohol)##STR3## The polyvinyl alcohols function best when they are essentiallyfully hydrolyzed, e.g., 5% or less acetyl groups, preferably 1% or lessresidual acetyl groups. The lower molecular weight PVA's function best,e.g., a weight average molecular weight of about 2,000 to about 10,000,but higher molecular weights also function, e.g., up to about 100,000.Another suitable water-soluble intercalant polymer is polyoxymethylene(POM), having monomer units ##STR4## which are water-soluble in the veryshort oligomer form, e.g., poly(formaldehyde) and having a melting pointof about 180° C., and weight average molecular weights from about 40 toabout 400.

The polyacrylic acid polymers and copolymers and partially or fullyneutralized salts, e.g., metal salts, are also suitable, having monomerunits: ##STR5## and are commercially available as CARBOPOL resins fromB. F. Goodrich and PRIMAL resins from Rohm & Haas. Light cross-linkingis acceptable, so long as water-solubility is retained. Weight averagemolecular weights, for the polyacrylic polymers and copolymers describedabove and below, of about 10,000 or less, e.g., 200-10,000, intercalatemore easily, but higher molecular weights up to about 100,000 or morealso function.

Other water-soluble derivatives of, and substituted, polyacrylic acidsalso are useful as intercalant polymers in accordance with the presentinvention, such as poly(methacrylic acid), (PMAA), having a monomericstructure: ##STR6##

Similar water-soluble polymers and copolymers that are suitable inaccordance with the present invention include poly(methacrylamide), orPMAAm, having a general monomeric structure: ##STR7##

Poly (N,N-Dimethylacrylamide), having the general monomeric structure:##STR8##

Poly (N-Isopropylacrylamide), or PIPAAm, having the monomeric structure:##STR9##

Poly(N-acetamidoacrylamide), having a monomeric structure: ##STR10## andPoly(N-acetmidomethacrylamide), having a monomeric structure: ##STR11##

Water-soluble copolymers including any one or more of theabove-described acrylic polymers also are useful in accordance with theprinciples of the present invention, including the acrylic interpolymersof polyacrylic acid and poly(methacrylic acid); polyacrylic acid withpoly(methacrylamide); and polyacrylic acid with methacrylic acid.

Other suitable water-soluble polymers include polyvinyloxazolidone (PVO)and polyvinylmethyloxazolidone (PVMO), having the monomeric structures:##STR12## Also suitable are polyoxypropylene, polyoxyethylene blockpolymers that conform to the formulas: ##STR13## wherein x and z areeach an integer in the range of about 4 to about 30; and y is an integerin the range of about 4 to about 100, for example Meroxapol 105;Meroxapol 108; Meroxapol 171; Meroxapol 172; Meroxapol 174; Meroxapol178; Meroxapol 251; Meroxapol 252; Meroxapol 254; Meroxapol 255;Meroxapol 258; Meroxapol 311; Meroxapol 312; and Meroxapol 314.

Other suitable water-soluble/water-dispersible intercalant polymersinclude polyacrylamide and copolymers of acrylamide; acrylamide/sodiumacrylate copolymer; acrylate/acrylamide copolymer; acrylate/ammoniummethacrylate copolymer; acrylates and copolymers of acrylic acid andsalts thereof; acrylate/diacetoneacrylamide copolymers;acrylate/steareth-20 methacrylate copolymer; acrylic/acrylatecopolymers; adipic acid/dimethylaminohydroxypropyl diethylenetriaminecopolymer; aminoethylacrylate phosphate/acrylate copolymer; ammoniumacrylate copolymers; ammonium styrene/acrylate copolymers; ammoniumvinyl acetate/acrylate copolymers; AMP acrylate/diacetoneacrylamidecopolymers; AMPD acrylate/diacetoneacrylamide copolymers;butadiene/acrylonitrile copolymer; butylate urea-formaldehyde resins;butyl benzoic acid/phthalic anhydride/trimethylolethane copolymer; butylester of ethylene/maleic anhydride copolymer; butyl ester of PVM/MAcopolymer; calcium/sodium PVM/MA copolymer; homopolymers of acrylic acidcross-linked with an allyl ether of pentaerythritol or an allyl ether ofsucrose, such as carbomer 910; carbomer 934; carbomer 934P; carbomer940; and carbomer 941; cornstarch/acrylamide/sodium acrylate copolymer;diethylene glycolamine/epichlorohydrin/piperazine copolymer;dodecanedioic acid/cetearyl alcohol/glycol copolymers; ethylene/acrylatecopolymers; ethylene/maleic anhydride copolymer; ethylene/vinyl acetatecopolymer; ethyl ester of PVM/MA copolymer; polyethyleneimines, such ashydroxyethyl/PEI-1000 and hydroxyethyl PEI-1500; isobutylene/maleicanhydride copolymer; isopropyl ester of PVM/MA copolymer;melamine/formaldehyde resin; methacryloyl ethyl betaine/methacrylatecopolymers; methoxy PEG-22/dodecyl glycol copolymer;methylstyrene/vinyltoluene copolymer; octadecene/maleic anhydridecopolymer; octylacrylamide/acrylate/butylaminoethyl methacrylatecopolymers; octylacrylamide/acrylate copolymers; PEG/dodecyl glycolcopolymers; polyethyleneimines, such as PEI-7; PEI-15; PEI-30; PEI-45;PEI-275; PEI-700; PEI-1000; PEI-1500; and PEI-2500; phthalicanhydride/glycerin/glycidyl decanoate copolymer;polyacrylamidomethylpropane sulfonic acid; polyacrylic acid;polyaminopropyl biguanide; polymeric quaternary ammonium salts, such aspolyquaternium-1; polyquaternium-2; polyquaternium-4; polyquaternium-5;polyquaternium-6; polyquaternium-7; polyquaternium-8; polyquaternium-9;polyquaternium-10; polyquaternium-11; polyquaternium-12;polyquaternium-13; polyquaternium-14; and polyquaternium-15; polyvinylacetate; polyvinyl alcohol; polyvinyl butyral; polyvinyl imidazoliniumacetate; potassium aluminum polyacrylate; PVM/MA copolymers;PVP/eicosene copolymers; PVP/ethyl methacrylate/methacrylic acidcopolymer; PVP/hexadecene copolymer; PVP/VA copolymer; PVP/vinylacetate/itaconic acid copolymer; sodium acrylate/vinyl alcoholcopolymers; sodium C₄ -C12 olefin/maleic acid copolymer; sodiumpolymethacrylate; sodium polynaphthalene sulfonate; sodium polystyrenesulfonate; sodium styrene/acrylate/PEG-10 dimaleate copolymer; estersand ethers of cellulose; sodium styrene/PEG-10 maleate/nonoxynol-10maleate/acrylate copolymer; starch/acrylate/acrylamide copolymers;styrene/acrylamide copolymer; styrene/acrylate/acrylonitrile copolymer;styrene/acrylate/ammonium methacrylate copolymer; styrene/acrylatecopolymer; styrene/maleic anhydride copolymer; styrene/PVO copolymer;sucrose benzoate/sucrose acetate isobutyrate/butyl benzyl phthalatecopolymer; sucrose benzoate/sucrose acetate isobutyrate/butylbenzylphthalate/methyl methacrylate copolymer; urea/formaldehyde resins;urea/melamine/formaldehyde resin; vinyl acetate/crotonate copolymers;vinyl acetate/crotonic acid copolymer; vinyl acetate/crotonicacid/methacryloxybenzophenone-1 copolymer; and vinyl acetate/crotonicacid/vinyl neodecanoate copolymer.

Other water-soluble polymeric polyols and polyhydric alcohols, such aspolysaccharides, also are suitable as polymer intercalants.

Suitable water-insoluble polymers include:

polyethers (polymers and copolymers) based on ethylene oxide,butylenoxide, propyleneoxide, phenols and bisphenols;

polyesters (polymers and copolymers) based on aliphatic and aromaticdiols, and aliphatic and aromatic dibasic acids; polyurethanes based onaliphatic and aromatic diisocyanates, and aliphatic and aromatic diols;

polyamides (polymers and copolymers) based on (1) aliphatic and aromaticdiamines, and aliphatic and aromatic dibasic acids; (b) aliphatic andaromatic amino acids;

polycarbonates (polymers and copolymers) based on carbonic acid andaromatic diols);

polycarbonimides (polymers and copolymers) based on dianhydride oftetrabasic acids and diamines and other heterochain polymers;

vinyl polymers and copolymers based on vinyl monomers, styrene andderivatives of styrene;

acryl polymers and copolymers based on acryl monomers;

copolymers based on styrene, vinyl and acryl monomers;

polyolefins polymers and copolymers based on ethylene, propylene andother alphaolefin monomers;

polymers and copolymers based on dienes, isobutylenes and the like; and

copolymers based on dienes, styrene, acryl and vinyl monomners.

The amount of intercalated layered material included in the matrixpolymer to form the composite material may vary widely depending on theintended use of the composite. For example, relatively, larger amountsof platelet particles (exclusive of the intercalant polymer, since theintercalant polymer content in the layered material may vary), i.e. fromabout 15% to about 30% by weight of the mixture, are used inapplications where articles are formed by stamping. Substantiallyenhanced barrier properties and heat resistance (deflection temperatureunder load, DTUL) are imparted by platelet particle concentrationsgreater than about 2.5%. Similarly, substantially enhanced strength isimparted by platelet particle concentrations greater than about 1.5%,including the nano-scale layered materials of this invention. It ispreferred that the platelet loading be less than about 10%. Plateletparticle loadings within the range of about 0.05% to about 40% byweight, preferably about 0.5% to about 20%, more preferably about 1% toabout 10% of the composite material significantly enhances modulus,dimensional stability, and wet strength. In general, the amount ofplatelet particles incorporated into a matrix polymer is less than about90% by weight of the mixture, and preferably from about 0.01% to about80% by weight of the composite material mixture, more preferably fromabout 0.05% to about 40% by weight of the polymer/particle mixture, andmost preferably from about 0.05% to about 20% or 0.05% to about 10% byweight, with some matrix polymers.

In accordance with an important feature of the present invention, theintercalated phyllosilicate can be manufactured in a concentrated form,e.g., 10-90%, preferably 20-80% intercalant polymer and 10-90%,preferably 20-80% intercalated phyllosilicate that can be dispersed inthe matrix polymer and exfoliated before or after addition to thepolymer melt to a desired platelet loading.

The intercalates are exfoliated and dispersed into one or more meltprocessible thermoplastic and/or thermosetting matrix polymerizablemonomers, oligomers or polymers, or mixtures thereof. Matrix polymersand water-soluble and/or water-insoluble intercalant polymers for use inthe process of this invention may vary widely, the only requirement isthat they are melt processible for later admixture with a matrixpolymer. In the preferred embodiments of the invention, the intercalantpolymer and the matrix polymer include at least 10, preferably at least30 recurring monomeric units. The upper limit to the number of recurringmonomeric units is not critical, provided that the melt index of thematrix polymer under use conditions is such that the matrix polymerforms a flowable mixture. Most preferably, the matrix polymer (orintercalant polymer) includes from at least about 10 to about 100recurring monomeric units. In the most preferred embodiments of thisinvention, the number of recurring units is such that the matrix polymerand/or intercalant polymer has a melt index of from about 0.01 to about12 grams per 10 minutes at the processing temperature.

Thermoplastic resins and rubbers for use as the matrix polymer and/or asan intercalant polymer, in the practice of this invention may varywidely. Illustrative of useful thermoplastic resins, which may be usedalone or in admixture, are polylactones such as poly(pivalolactone),poly(caprolactone) and the like; polyurethanes derived from reaction ofdiisocyanates such as 1,5-naphthalene diisocyanate; p-phenylenediisocyanate, m-phenylene diisocyanate, 2,4-toluene diisocyanate,4,4'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-diphenyl-methanediisocyanate, 3,3-'dimethyl-4,4'-biphenyl diisocyanate,4,4'-diphenylisopropylidene diisocyanate, 3,3'-dimethyl-4,4'-diphenyldiisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate,3,3'-dimethoxy-4,4'-biphenyl diisocyanate, dianisidine diisocyanate,toluidine diisocyanate, hexamethylene diisocyanate,4,4'-diisocyanatodiphenylmethane and the like and linear long-chaindiols such as poly(tetramethylene adipate), poly(ethylene adipate),poly(1,4-butylene adipate), poly(ethylene succinate), poly(2,3-butylenesuccinate), polyether diols and the like; polycarbonates such as poly[methane bis(4-phenyl)carbonate], poly [1,1-etherbis(4-phenyl)carbonate], poly [diphenylmethane bis(4-phenyl)carbonate],poly [1,1-cyclohexane bis(4-phenyl)carbonate] and the like;polysulfones; polyethers; polyketones; polyamides such as poly(4-aminobutyric acid), poly(hexamethylene adipamide), poly(6-aminohexanoicacid), poly(m-xylylene adipamide), poly(p-xylyene sebacamide),poly(2,2,2-trimethyl hexamethylene terephthalamide), poly(metaphenyleneisophthalamide) (NOMEX), poly(p-phenylene terephthalamide) (KEVLAR), andthe like; polyesters such as poly(ethylene azelate),poly(ethylene-1,5-naphthalate, poly(1,4-cyclohexane dimethyleneterephthalate), poly(ethylene oxybenzoate) (A-TELL), poly(para-hydroxybenzoate) (EKONOL), poly(1,4-cyclohexylidene dimethylene terephthalate)(KODEL) (as), poly(1,4-cyclohexylidene dimethylene terephthalate)(Kodel) (trans), polyethylene terephthalate, polybutylene terephthalateand the like; poly(arylene oxides) such aspoly(2,6-dimethyl-1,4-phenylene oxide), poly(2,6-diphenyl-1,4-phenyleneoxide) and the like; poly(arylene sulfides) such as poly(phenylenesulfide) and the like; polyetherimides; vinyl polymers and theircopolymers such as polyvinyl acetate, polyvinyl alcohol, polyvinylchloride; polyvinyl butyral, polyvinylidene chloride, ethylene-vinylacetate copolymers, and the like; polyacrylics, polyacrylate and theircopolymers such as polyethyl acrylate, poly(n-butyl acrylate),polymethylmethacrylate, polyethyl methacrylate, poly(n-butylmethacrylate), poly(n-propyl methacrylate), polyacrylamide,polyacrylonitrile, polyacrylic acid, ethylene-acrylic acid copolymers,ethylene-vinyl alcohol copolymers acrylonitrile copolymers, methylmethacrylate-styrene copolymers, ethylene-ethyl acrylate copolymers,methacrylated butadiene-styrene copolymers and the like; polyolefinssuch as low density poly(ethylene), poly(propylene), chlorinated lowdensity poly(ethylene), poly(4-methyl -1-pentene), poly(ethylene),poly(styrene), and the like; ionomers; poly(epichlorohydrins);poly(urethane) such as the polymerization product of one or more diolssuch as ethylene glycol, propylene glycol and/or a polydiol, such asdiethylene glycol, triethylene glycol and/or tetraethylene glycol, andthe like, with a polyisocyanate such as 2,4-tolylene diisocyanate,2,6-tolylene diisocyante, 4,4'-diphenylmethane diisocyanate,1,6-hexamethylene diisocyanate, 4,4'-dicycohexylmethane diisocyanate andthe like; and polysulfones such as the reaction product of the sodiumsalt of 2,2-bis(4-hydroxyphenyl)propane and 4,4'-dichlorodiphenylsulfone; furan resins such as poly(furan); cellulose ester plastics suchas cellulose acetate, cellulose acetate butyrate, cellulose propionateand the like; silicones such as poly(dimethyl siloxane), poly(dimethylsiloxane), poly(dimethyl siloxane co-phenylmethyl siloxane), and thelike; protein plastics; and blends of two or more of the foregoing.

Vulcanizable and thermoplastic rubbers useful as the matrix polymerand/or as a water-insoluble intercalant polymer, in the practice of thisinvention may also vary widely. Illustrative of such rubbers arebrominated butyl rubber, chlorinate butyl rubber, polyurethaneelastomers, fluoroelastomers, polyester elastomers, polyvinylchloride,butadiene/acrylonitrile elastomers, silicone elastomers,poly(butadiene), poly(isobutylene), ethylene-propylene copolymers,ethylene-propylene-diene terpolymers, sulfonatedethylene-propylene-diene terpolymers, poly(chloroprene),poly(2,3-dimethylbutadiene), poly(butadiene-pentadiene),chlorosulphonated poly(ethylenes), poly(sulfide) elastomers, blockcopolymers, made up of segments of glassy or crystalline blocks such aspoly(styrene), poly(vinyltoluene), poly(t-butyl styrene), polyesters andthe like and the elastomeric blocks such as poly(butadiene),poly(isoprene), ethylene-propylene copolymers, ethylene-butylenecopolymers, polyether and the like as for example the copolymers inpoly(styrene)-poly(butadiene)-poly(styrene) block copolymer manufacturedby Shell Chemical Company under the trade name KRATON®.

Useful thermosetting resins include, for example, the polyamides;polyalkylamides; polyesters; polyurethanes; polycarbonates;polyepoxides; and mixtures thereof. Thermoset resins based onwater-soluble prepolymers, include prepolymers based on formaldehyde:phenols (phenol, cresol and the like); urea; melamine; melamine andphenol; urea and phenol. Polyurethanes based on: toluene diisocyanate(TDI) and monomeric and polymeric diphenyl methanediisocyanates (MDI);hydroxy terminated polyethers (polyethylene glycol, polypropyleneglycol, copolymers of ethylene oxide and propylene oxide and the like);amino terminated polyethers, polyamines (tetramethylene diamine,ethylenediamine, hexamethylenediamine, 2,2-dimethyl 1,3-propanediamine;melamine, diaminobenzene, triaminobenzene and the like); polyamidoamines(for instance, hydroxy terminated polyesters); unsaturated polyestersbased on maleic and fumaric anhydrides and acids; glycols (ethylene,propylene), polyethylene glycols, polypropylene glycols, aromaticglycols and polyglycols; unsaturated polyesters based on vinyl, allyland acryl monomers; epoxides, based on biphenol A(2,2'-bis(4-hydroxyphenyl)propane) and epichlorohydrin; epoxyprepolymers based on monoepoxy and polyepoxy compounds and α,βunsaturated compounds (styrene, vinyl, allyl, acrylic monomers);polyamides 4-tetramethylene diamine, hexamethylene diamine, melamine,1,3-propanediamine, diaminobenzene, triaminobenzene,3,3',4,4'-bitriaminobenzene; 3,3',4,4'-biphenyltetramine and the like).Polyethyleneimines; amides and polyamides (amides of di-, tri-, andtetra acids); hydroxyphenols (pyrogallol, gallic acid,tetrahydroxybenzophenone, tetrahydroquinone, catechol, phenol and thelike); anhydrides and polyandrides of di-, tri-, and tetraacids;polyisocyanurates based on TDI and MDI; polyimides based on pyromelliticdianhydride and 1,4-phenyldiamine; polybenzimidozoles based on 3 3',44'-biphenyltetramine and isophthalic acid; polyamide based onunsaturated dibasic acids and anhydrides (maleic, fumaric) and aromaticpolyamides; alkyd resins based on dibasic aromatic acids or anhydrides,glycerol, trimethylolpropane, pentaerythritol, sorbitol and unsaturatedfatty long chain carboxylic acids (the latter drived from vegetableoils); and prepolymers based on acrylic monomers (hydroxy or carboxyfunctional).

Most preferred thermoplastic polymers useful as the matrix polymerand/or as an intercalant polymer, are thermoplastic polymers such aspolyamides, polyesters, and polymers of alpha-beta unsaturated monomersand copolymers. Polyamides which may be used in the process of thepresent invention are synthetic linear polycarbonamides characterized bythe presence of recurring carbonamide groups as an integral part of thepolymer chain which are separated from one another by at least twocarbon atoms. Polyamides of this type include polymers, generally knownin the art as nylons, obtained from diamines and dibasic acids havingthe recurring unit represented by the general formula:

    --NHCOR.sup.13 COHNR.sup.14 --

in which R¹³ is an alkylene group of at least 2 carbon atoms, preferablyfrom about 2 to about 11, or arylene having at least about 6 carbonatoms, preferably about 6 to about 17 carbon atoms; and R¹⁴ is selectedfrom R¹³ and aryl groups. Also, included are copolyamides andterpolyamides obtained by known methods, for example, by condensation ofhexamethylene diamine and a mixture of dibasic acids consisting ofterephthalic acid and adipic acid. Polyamides of the above descriptionare well-known in the art and include, for example, the copolyamide of30% hexamethylene diammonium isophthalate and 70% hexamethylenediammonium adipate, poly(hexamethylene adipamide) (nylon 6,6),poly(hexamethylene sebacamide) (nylon 6, 10), poly(hexamethyleneisophthalamide), poly(hexamethylene terephthalamide),poly(heptamethylene pimelamide) (nylon 7,7), poly(octamethylenesuberamide) (nylon 8,8 ), poly(nonamethylene azelamide) (nylon 9,9)poly(decamethylene azelamide) (nylon 10,9), poly(decamethylenesebacamide) (nylon 10,10), poly[bis(4-aminocyclohexyl)methane-1,10-decanecarboxamide)], poly(m-xylene adipamide),poly(p-xylene sebacamide), poly(2,2,2-trimethyl hexamethyleneterephthalamide), poly(piperazine sebacamdie), poly(p-phenyleneterephthalamide), poly(metaphenylene isophthalamide) and the like.

Other polyamides useful as the matrix polymer and/or as an intercalantpolymer, are those formed by polymerization of amino acids andderivatives thereof, as, for example, lactams. Illustrative of theseuseful polyamides are poly(4-aminobutyric acid) (nylon 4),poly(6-aminohexanoic acid) (nylon 6), poly(7-aminoheptanoic acid) (nylon7), poly(8-aminooctanoic acid) (nylon 8), poly(9-aminononanoic acid)(nylon 9), poly(10-amino-decanoic acid) (nylon 10),poly(11-aminoundecanoic acid) (nylon 11), poly(12-aminododecanoic acid)(nylon 12) and the like.

Preferred polyamides are poly(caprolactam), poly(12-aminododecanoicacid) and poly(hexamethylene adipamide).

Other matrix (host) polymers useful as the matrix polymer and/or as anintercalant polymer, which may be employed in admixture with exfoliatesto form nanocomposites, are linear polyesters. The type of polyester isnot critical and the particular polyesters chosen for use as the matrixpolymer and/or as the intercalant polymer will depend essentially on thephysical properties and features, i.e., tensile strength, modulus andthe like, desired in the final form. Thus, a multiplicity of linearthermoplastic polyesters having wide variations in physical propertiesare suitable for use as the intercalant polymers and/or as matrixpolymers in admixture with exfoliated layered material platelets inmanufacturing nanocomposites in accordance with this invention.

The particular polyester chosen for use can be a homo-polyester or aco-polyester, or mixtures thereof, as desired. Polyesters are normallyprepared by the condensation of an organic dicarboxylic acid and anorganic diol, and, the reactants can be added to the intercalates, orexfoliated intercalates for in situ polymerization of the polyesterwhile in contact with the layered material, before or after exfoliationof the intercalates.

Polyesters which are suitable for use as the matrix polymer and/or as anintercalant polymer, in this invention are those which are derived fromthe condensation of aromatic, cycloaliphatic, and aliphatic diols withaliphatic, aromatic and cycloaliphatic dicarboxylic acids and may becycloaliphatic, aliphatic or aromatic polyesters.

Exemplary of useful cycloaliphatic, aliphatic and aromatic polyesterswhich can be utilized as the matrix polymer and/or as an intercalantpolymer, in the practice of the present invention are poly(ethyleneterephthalate), poly(cyclohexlenedimethylene terephthalate),poly(ethylene dodecate), poly(butylene terephthalate),poly[ethylene(2,7-napthalate)], poly(methaphenylene isophthalate),poly(glycolic acid), poly(ethylene succinate), poly(ethylene adipate),poly(ethylene sebacate), poly(decamethylene azelate), poly(ethylenesebacate), poly(decamethylene adipate), poly(decamethylene sebacate),poly(dimethylpropiolactone), poly(parahydroxybenzoate) (EKONOL),poly(ethylene oxybenzoate) (A-tell), poly(ethylene isophthalate),poly(tetramethylene terephthalate, poly(hexamethylene terephthalate),poly(decamethylene terephthalate), poly(1,4-cyclohexane dimethyleneterephthalate) (trans), poly(ethylene 1,5-naphthalate), poly(ethylene2,6-naphthalate), poly(1,4-cyclohexylidene dimethylene terephthalate),(KODEL) (cis), and poly(1,4-cyclohexylidene dimethylene terephthalate(KODEL) (trans).

Polyester compounds prepared from the condensation of a diol and anaromatic dicarboxylic acid are especially suitable for use as the matrixpolymer and/or as a water-insoluble intercalant polymer, in accordancewith the present invention. Illustrative of such useful aromaticcarboxylic acids are terephthalic acid, isophthalic acid and ano-phthalic acid, 1,3-napthalene-dicarboxylic acid,1,4-napthalenedicarboxylic acid, 2,6-napthalenedicarboxylic acid,2,7-napthalene-dicarboxylic acid, 4,4'-diphenyldicarboxylic acid,4,4,'-diphenylsulfone-dicarboxylic acid,1,1,3-trimethyl-5-carboxy-3-(p-carboxyphenyl)-idane, diphenyl ether4,4'-dicarboxylic acid, bis-p(carboxyphenyl) methane and the like. Ofthe aforementioned aromatic dicarboxylic acids, those based on a benzenering (such as terephthalic acid, isophthalic acid, orthophthalic acid)are preferred for use in the practice of this invention. Among thesepreferred acid precursors, terephthalic acid is particularly preferredacid precursor.

The most preferred embodiments of this invention incorporate theintercalate into a matrix polymer selected from the group consisting ofpoly(ethylene terephthalate), poly(butylene terephthalate),poly(1,4-cyclohexane dimethylene terephthalate), a polyvinylimine, andmixture thereof. Among these polyesters of choice, poly(ethyleneterephthalate) and poly(butylene terphthalate) are most preferred.

Still other useful thermoplastic homopolymers and copolymers for use asthe matrix polymer and/or as an intercalant polymer, for formingnanocomposites are polymers formed by polymerization ofalpha-beta-unsaturated monomers or the formula:

    R.sup.15 R.sup.16 C═CH.sub.2

wherein:

R¹⁵ and R¹⁶ are the same or different and are cyano, phenyl, carboxy,alkylester, halo, alkyl, alkyl substituted with one or more chloro orfluoro, or hydrogen. Illustrative of such preferred homopolymers andcopolymers are homopolymers and copolymers of ethylene, propylene,vinylalcohol, acrylonitrile, vinylidene chloride, esters of acrylicacid, esters of methacrylic acid, chlorotrifluoroethylene, vinylchloride and the like. Preferred are poly(propylene), propylenecopolymers, poly(ethylene) and ethylene copolymers. More preferred arepoly(ethylene) and poly(propylene).

In the preferred embodiments of the invention, the polymers of choicefor use as the matrix polymer and/or as the intercalant polymer inmanufacturing nanocomposites are polymers and copolymers of olefins,polyesters, polyamides, polyvinylimines, and blends thereof containingpolyesters. In the particularly preferred embodiments of the invention,polymers and copolymers of ethylene, polyamides (preferably nylon 6 andnylon 66 and more preferably nylon 6), and blends thereof can be usedfor intercalation of the layered material, and as the matrix polymer.

The mixture may include various optional components which are additivescommonly employed with polymers. Such optional components includenucleating agents, fillers, plasticizers, impact modifiers, chainextenders, colorants, mold release lubricants, antistatic agents,pigments, fire retardants, and the like. These optional components andappropriate amounts are well known to those skilled in the art.

Exfoliation of the intercalated layered material should providedelamination of at least about 90% by weight of the intercalatedmaterial to provide a composition comprising a polymeric matrix havingplatelet particles substantially homogeneously dispersed therein. Someintercalates require a shear rate that is greater than about 10 sec⁻¹for such relatively thorough exfoliation. Other intercalates exfoliatenaturally or by heating to the melt temperature of the intercalantpolymer, or by applying low pressure, e.g., 0.5 to 60 atmospheres aboveambient, with or without heating. The upper limit for the shear rate isnot critical provided that the shear rate is not so high as tophysically degrade the polymer. In the particularly preferredembodiments of the invention, when shear is employed for exfoliation,the shear rate is from greater than about 10 sec⁻¹ to about 20,000 sec⁻¹and in the more preferred embodiments of the invention the shear rate isfrom about 100 sec⁻¹ to about 10,000 sec⁻¹.

When shear is employed for exfoliation, any method can be used to applya shear to a flowable mixture of any polymer melt. The shearing actioncan be provided by any appropriate method, as for example by mechanicalmeans, by thermal shock, by pressure alteration, or by ultrasonics, allknown in the art. In particularly useful procedures, the flowablepolymer mixture is sheared by mechanical methods in which portions ofthe melt are caused to flow past other portions of the mixture by use ofmechanical means, such as stirrers, Banbury® type mixers, Brabender®type mixers, long continuous mixers, and extruders. Another procedureemploys thermal shock in which shearing is achieved by alternativelyraising or lowering the temperature of the mixture causing thermalexpansions and resulting in internal stresses which cause the shear. Instill other procedures, shear is achieved by sudden pressure changes inpressure alteration methods; by ultrasonic techniques in whichcavitation or resonant vibrations cause portions of the mixture tovibrate or to be excited at different phases and thus subjected toshear. These methods of shearing flowable polymer mixtures and polymermelts are merely representative of useful methods, and any method knownin the art for shearing flowable polymer mixtures and polymer melts maybe used.

Mechanical shearing methods may be employed such as by extrusion,injection molding machines, Banbury® type mixers, Brabender® type mixersand the like. Shearing also can be achieved by introducing the polymermelt at one end of the extruder (single or double screw) and receivingthe sheared polymer at the other end of the extruder. The temperature ofthe polymer melt, the length of the extruder, residence time of the meltin the extruder and the design of the extruder (single screw, twinscrew, number of flights per unit length, channel depth, flightclearance, mixing zone, etc.) are several variables which control theamount of shear to be applied.

Exfoliation should be sufficiently thorough to provide at least about80% by weight, preferably at least about 85% by weight, more preferablyat least about 90% by weight, and most preferably at least about 95% byweight delamination of the layers to form platelet particlessubstantially homogeneously dispersed in the matrix polymer. As formedby this process, the platelet particles dispersed in matrix polymershave the thickness of the individual layers, or small multiples lessthan about 10, preferably less than about 5 and more preferably lessthan about 3 of the layers, and still more preferably 1 or 2 layers. Inthe preferred embodiments of this invention, intercalation anddelamination of every interlayer space is complete so that all orsubstantially all individual layers delaminate one from the other toform separate platelet particles. In cases where intercalation isincomplete between some layers, those layers will not delaminate in apolymer melt, and will form platelet particles comprising those layersin a coplanar aggregate.

The effect of adding into a matrix polymer the nanoscale particulatedispersed platelet particles, derived from the intercalates formed inaccordance with the present invention, typically is an increase intensile modulus and ultimate tensile strength or an increase in ultimateimpact resistance or glass transition temperature (Tg).

Molding compositions comprising a thermoplastic or thermosetting polymercontaining a desired loading of platelets obtained from exfoliation ofthe intercalates manufactured according to the invention areoutstandingly suitable for the production of sheets and panels havingvaluable properties. Such sheets and panels may be shaped byconventional processes such as vacuum processing or by hot pressing toform useful objects. The sheets and panels according to the inventionare also suitable as coating materials for other materials comprising,for example, wood, glass, ceramic, metal or other plastics, andoutstanding strengths can be achieved using conventional adhesionpromoters, for example, those based on vinyl resins. The sheets andpanels can also be laminated with other plastic films and this ispreferably effected by co-extrusion, the sheets being bonded in themolten state. The surfaces of the sheets and panels, including those inthe embossed form, can be improved or finished by conventional methods,for example by lacquering or by the application of protective films.

The polymer/platelet composite materials are especially useful forfabrication of extruded films and film laminates, as for example, filmsfor use in food packaging. Such films can be fabricated usingconventional film extrusion techniques. The films are preferably fromabout 10 to about 100 microns, more preferably from about 20 to about100 microns and most preferably from about 25 to about 75 microns inthickness.

The homogeneously distributed platelet particles and matrix polymer thatform the nanocomposites are formed into a film by suitable film-formingmethods. Typically, the composition is melted and forced through a filmforming die. The film of the nanocomposite may go through steps to causethe platelets to be further oriented so the major planes through theplatelets are substantially parallel to the major plane through thefilm. A method to do this is to biaxially stretch the film. For example,the film is stretched in the axial or machine direction by tensionrollers pulling the film as it is extruded from the die. The film issimultaneously stretched in the transverse direction by clamping theedges of the film and drawing them apart. Alternatively, the film isstretched in the transverse direction by using a tubular film die andblowing the film up as it passes from the tubular film die. The filmsmay exhibit one or more of the following benefits: increased modulus;increased wet strength; increased dimensional stability; decreasedmoisture adsorption; decreased permeability to gases such as oxygen andliquids, such as water, alcohols and other solvents.

The following specific examples are presented to more particularlyillustrate the invention and are not to be construed as limitationsthereon.

EXAMPLE 1 Preparation of Clay--PVP Complexes (Intercalates)

Materials:

Clay--sodium montmorillonite;

PVP--molecular weights of 10,000 and 40,000.

To prepare Clay (sodium montmorillonite)--PVP complexes (intercalates)we used three different processes for polymer intercalation:

1. Mixture of the 2% PVP/water solution with the 2% clay/watersuspension in a ratio sufficient to provide a polymer concentration ofat least about 16% based on the dry weight of the clay.

2. Dry clay powder (about 8% by weight moisture) was gradually added tothe 2% PVP/water solution in a ratio sufficient to provide a polymerconcentration of at least about 16% based on the dry weight of the clay.

3. Dry PVP was mixed with dry clay, the mixture was hydrated with 35-38%of water, based on the dry weight of the clay, and then extruded.

Mixtures 1 and 2 were agitated at room temperature during 4 hours.

The weight ratio Clay:PVP was changed from 80:20 to 20:80.

These experiments show that the intercalation and exfoliation methods ofthe present invention yielded the Clay--PVP complexes (intercalates),and the results of the intercalation do not depend on the method ofpreparation (1, 2, or 3) or molecular weight of the intercalant polymer(PVP), but do depend on the quantity of polymer sorbed between clayplatelets. In Table 1 the results of the X-ray diffraction for Clay--PVPcomplexes with different ratios of components are demonstrated. The plotof these data is shown in FIG. 1. From these data (Table 1, FIG. 1) onecan see the step character of intercalation while the polymer is beingsorbed in the interlayer space between adjacent platelets of themontmorillonite clay. There are increasing d(001) values from 12 Å forclay with no PVP sorbed to 24-25 Å spacing between adjacent plateletswith sorption of 20-30% PVP. The next step to 30-32 Å spacing occurswhen the sorbed PVP content is increased to 40-60%. Further increasingthe sorbed PVP content to 70-80% increases the d(001) values to 40-42 Å.There are d(002) reflexes together with d(001) reflexes in X-raypatterns of all complexes obtained (Table 1, FIG. 1). This indicates theregularity of Clay--PVP complex structures.

                  TABLE 1                                                         ______________________________________                                        PVP, %*           d(001), Å                                                                          d(002), Å                                      ______________________________________                                        1        0.0          12.4      6.2                                           2       20.0          24.0     11.4                                           3       30.0          25.0     12.0                                           4       40.0          30.0     15.2                                           5       45.0          31.0     15.2                                           6       50.0          30.0     15.5                                           7       55.0          32.0     16.5                                           8       60.0          34.0     17.0                                           9       70.0          40.0     21.0                                           10      80.0          42.0     21.0                                           ______________________________________                                         *Percent by weight, based on the dry weight of the clay.                 

EXAMPLE 2 Preparation of Clay--PVA Complexes (Intercalates)

Materials:

Clay--sodium montmorillonite;

PVA--degree of hydrolysis 75-99%,--molecular weights of 5,000 and 8,000.

To prepare Clay (sodium montmorillonite)--PVA complexes (intercalates)we provided three different processes for polymer intercalation:

1. Mixture of the 2% PVA/water solution with the 2% clay/watersuspension in a ratio sufficient to provide a polymer concentration ofat least about 16% based on the dry weight of the clay.

2. Dry clay powder was gradually added to the 2% PVA/water solution in aratio sufficient to provide a polymer concentration of at least about16% based on the dry weight of the clay.

3. Dry clay was moisturized with PVA/water solution to 20-80% by weightwater, and then extruded.

The mixtures 1 and 2 were agitated at room temperature during 4 hours.

The weight ratio Clay:PVA was changed from 80:20 to 20:80.

Some of the exfoliates were studied by X-ray diffraction. Theseexperiments show that all methods of the present invention forintercalation yielded the composite Clay--PVA complexes (intercalates),and the results of the intercalation do not depend on the method ofpreparation (1, 2, or 3), or molecular weight of the intercalant polymer(PVA), or degree of hydrolysis, but do depend on the quantity of PVAsorbed between clay platelets. In Table 2 the results of the X-raydiffraction for Clay--PVA complexes with different ratios of componentsare demonstrated. The plot of these data is shown in FIG. 2. From thesedata (Table 2, FIG. 2) one can see the step character of increasingd(001) values from 12 Å for clay with no sorbed PVA to 22-25 Å spacingbetween adjacent platelets with sorption of 20-30% PVA. The next step to30-33 Å occurs when the sorbed PVA content increases to 35-50%. Afurther increase of the sorbed PVA content to 60-80% increases thed(001) values to 40-45 Å.

Heating of samples at 120° C. during 4 hours insignificantly changed thed(001) values (Table 2, FIG. 2).

                  TABLE 2                                                         ______________________________________                                                                   d(001), Å                                      PVA %*            d(001), Å                                                                          120° C.                                     ______________________________________                                        1        0.0          12.4                                                    2       20.0          23.0     22.0                                           3       30.0          25.0     24.0                                           4       35.0          32.0     32.0                                           5       40.0          31.0     30.0                                           6       45.0          33.0     32.0                                           7       50.0          32.0     32.0                                           8       60.0          42.0     42.0                                           9       70.0          44.0     42.0                                           10      80.0          45.0     44.0                                           ______________________________________                                         *Percent by weight, based on the dry weight of the clay.                 

The graphs of FIGS. 3-5 are x-ray diffraction patterns of blends ofdifferent water-soluble polymers with sodium bentonite clay. The patternof FIGS. 3 and 4 are taken from intercalated clay 20% by weightpolyvinylpyrrolidone (weight average molecular weight =10,000 for FIG.3; 40,000 for FIG. 4) and 80% by weight sodium bentonite clay. Theblends were formed by mixing the PVP and clay from a 2% solution of PVPand a 2% dispersion of sodium bentonite in a 1:4 ratio, respectively. Asshown, the PVP:clay complexed since no d(001) smectite peak appears atabout 12.4 Å. Similar results are shown for 20% polyvinyl alcohol, 80%sodium bentonite, as shown in FIG. 5, blended in the same way and in thesame ratio. The d(001) peak of non-exfoliated (layered) sodium bentoniteclay appears at about 12.4 Å, as shown in the x-ray diffraction patternfor sodium bentonite clay (containing about 10% by weight water) in thelower x-ray diffraction patterns of FIGS. 6 and 7. The graphs of FIG. 6are x-ray diffraction patterns of sodium bentonite clay(montmorillonite) and a PVP:clay complex that was obtained by extrusionof a blend of 20% by weight polyvinylpyrrolidone (molecular weight10,000) and 80% sodium bentonite clay (containing a crystobaliteimpurity, having a d-spacing of about 4.05 Å) with 35% water by weightof dry clay. As shown in FIG. 6, the PVP clay complexed since no d(001)smectite peak appears at about 12.4 Å. There are basil spacings with ad(001) peak of PVP:clay complex at about 24 Å and d(002) peak ofPVP:clay complex at about 12 Å, that shows close to regular structure ofthis intercalated composite with a PVP:clay ratio equal to 1:4. Thegraphs of FIG. 7 are x-ray diffraction patterns of sodium bentonite clay(montmorillonite) and PVP:clay complex that was obtained by extrusion ofblend of 50% by weight polyvinylpyrrolidone (molecular weight 10,000)and 50% of sodium bentonite clay (containing a crystobalite impurity,having d-spacing of about 4.05 Å) with 35% water by weight of dry clay.As shown in FIG. 7, the PVP:clay complexed since no d(001) smectite peakappears at about 12.4 Å. There are basil spacings with a d(001) peak ofthe PVP:clay complex at about 32 Å and a d(002) peak of PVP:clay complexat about 16 Å that shows close to regular structure of this intercalatedcomposite with a PVP:clay ratio equal to 1:1. When mechanical blends ofpowdered sodium bentonite clay (containing about 10% by weight water)and powdered polyvinylpyrrolidone (PVP) polymer were mixed with water(about 75% by weight clay), the polymer was intercalated between thebentonite clay platelets, and an exothermic reaction occurred that, itis theorized, resulted from the polymer being bonded to the internalfaces of the clay platelets sufficiently for exfoliation of theintercalated clay.

It should be noted, also, that exfoliation did not occur unless thebentonite clay included water in an amount of at least about 5% byweight, based on the dry weight of the clay, preferably about 10% toabout 15% water. The water can be included in the clay as received, orcan be added to the clay prior to or during polymer contact.

It should also be noted that the exfoliation occurred withoutshearing--the layered clay exfoliated naturally after sufficientintercalation of polymer between the platelets of the layeredbentonite--whether the intercalate was achieved by using sufficientwater, e.g., about 20% to about 80% by weight, based on the dry weightof the clay, for sufficient migration of the polymer into the interlayerspaces, and preferably also extruding; or by heating the blends to atleast the intercalant polymer melt temperature, while the clay includesat least about 5% by weight water, for polymer intercalation.

The x-ray diffraction pattern of FIG. 8 shows that at a ratio of 80%PVP, 20% clay, the periodicity of the intercalated composite with PVPclay ratio equal to 4:1 is increased to about 41 Å.

EXAMPLE 3

The upper x-ray diffraction pattern shown in FIG. 9 was taken on amechanical blend of 80% by weight polyamide and 20% by weight sodiumbentonite clay. The lower x-ray diffraction pattern was taken on 100%sodium bentonite clay. The polyamide was not intercalated between theclay platelets since the blend was dry (clay contained about 8% byweight water) and the polyamide was not melted. As shown in FIG. 9, bothdiffraction patterns show the characteristic d(001) 12.45 Å and thed(020) 4.48 Å peaks characteristic of non-exfoliated smectite clays anda 4.05 Å peak characteristic of a crystobalite impurity.

As shown in FIG. 10, when the 80% polyamide, 20% sodium bentonitemechanical blend was heated to the polyamide melt temperature, andpreferably at least about 40°-50° C. above, the polymer melt temperaturefor faster intercalation, e.g., 230° C., (see the upper x-raydiffraction pattern for the melt) the smectite d(001) peak at 12.45 Åwas no longer present, since the polyamide was intercalated between theclay platelets and the platelets were exfoliated, thereby eliminatingthe d(001) periodicity characteristic of aligned smectite platelets. Themechanical blend was melted by heating the blend to the melt temperatureunder a N₂ head space to avoid oxidation. The lower x-ray diffractionpattern in FIG. 10 again is the 100% sodium bentonite pattern forcomparison.

Alternatively, the mechanical blend could be blended with about 10% byweight, preferably about 20% to about 50% by weight water or organicsolvent, based on the total weight of the blend, and extruded to achieveintercalation and exfoliation.

EXAMPLE 4

Similar to FIG. 9, the x-ray diffraction pattern shown in FIG. 11 wastaken from a mechanical blend of 70% by weight dimethylterephthalate and30% by weight sodium bentonite clay. Because of the different scales ofFIG. 11 versus FIG. 9, the d(001) smectite peak at about 12.4 Å is notas high. The lower x-ray diffraction pattern of FIG. 11 is from 100%dimethylterephthalate. As shown in FIG. 12, when the mechanical blendwas subjected to a temperature above the dimethylterephthalate melttemperature, about 230° C., the d(001) 12.4 Å smectite peak disappearedsince the clay was intercalated with the polymer and exfoliated (lowerpattern), while it appears for the mechanical blend (upper pattern).

EXAMPLE 5

The upper x-ray diffraction pattern of FIG. 13 was taken from a melt of90% by weight polyethylene terephthalate (PET) and 10% by weight sodiumbentonite clay (containing about 8% by weight moisture). The lowerpattern was taken from 100% sodium bentonite, showing the characteristicsmectite d(001) peak at about 12.4 (12.37) Å, and the characteristicd(020) peak at 4.47 Å. When heated to the PET melt temperature (upperx-ray diffraction pattern), the d(001) smectite peak disappeared sincethe PET was intercalated between the clay platelets and the plateletswere exfoliated.

EXAMPLE 6

FIG. 14 shows x-ray diffraction patterns from a melted (230° C.) blendof 60% by weight hyxroxyethylterephthalate (HETPh) and 40% by weightsodium bentonite (containing about 8% by weight moisture), for the lowerpattern, and 100% HETPh for the upper pattern. As shown, nocharacteristic smectite d(001) peak appears at about 12.4 Å for themelted blend while there is the characteristic d(020) peak at about 4.48Å, indicating that the clay was intercalated with the HETPh, and theplatelets were exfoliated.

EXAMPLE 7

FIG. 15 shows x-ray diffraction patterns from a melted (250° C.) blendof 70% by weight hydroxybutylterephthalate (HBTPh) and 30% sodiumbentonite (containing about 8% by weight moisture). As shown, nocharacteristic smectite d(001) peak appears at about 12.4 Å for themelted blend, indicating that the clay was intercalated with the HBTPh,and the platelets were exfoliated.

EXAMPLE 8

FIG. 16 shows an x-ray diffraction pattern from a melted (280° C.) blendof 50% by weight polycarbonate and 50% by weight sodium bentonite(containing about 8% by weight moisture). As shown, no characteristicsmectite d(001) peak appears at about 12.4 Å for the melted blend,indicating that the clay was intercalated with the polycarbonate, andthe platelets were exfoliated.

FIGS. 1-8 show that the exfoliation methods of the present inventionyielded the composite Clay--polymer complexes (intercalates), and theresults of the intercalation do not depend on the molecular weight ofthe intercalant polymer, but do depend on the amount of polymer sorbedbetween clay platelets. From these data one can see the step characterof increasing d(001) values from about 12 Å for clay with no sorbedpolymer to 22-25 Å spacing between adjacent platelets with sorption of20-30% polymer. The next step to 30-33 Å occurs when the sorbed polymercontent increases to 35-50%. A further increase of the sorbed polymercontent to 60-80% increases the d(001) values to 40-45 Å.

As shown in the graphs of FIGS. 914 15, when the mechanical blends wereheated to the polymer melt temperature, and preferably at least about40°-50° C. above the polymer melt temperature for faster reaction(intercalation, exfoliation), the polymer melt was intercalated betweenthe bentonite clay platelets.

It should be noted, also, that exfoliation did not occur unless thebentonite clay included water in an amount of at least about 5% byweight, based on the dry weight of the clay, preferably about 10% toabout 15% water. The water can be included in the clay as received, orcan be added to the clay prior to or during polymer contact.

Numerous modifications and alternative embodiments of the invention willbe apparent to those skilled in the art in view of the foregoingdescription. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the best mode of carrying out the invention. The details of thestructure may be varied substantially without departing from the spiritof the invention, and the exclusive use of all modifications which comewithin the scope of the appended claims is reserved.

What is claimed is:
 1. An intercalate, capable of being exfoliated intoindividual phyllosilicate platelets, said intercalate manufactured byextruding a mixture of a phyllosilicate; an intercalant polymer having afunctionality selected from the group consisting of an aromatic ring;carbonyl; carboxyl; hydroxyl; amine; amide; ether and ester structures;and water through a die-opening, said water present in the mixture in anamount of at least about 20% by weight based on the dry weight of thephyllosilicate, and said polymer present in the mixture in an amount of16% to about 80% by weight, based on the dry weight of phyllosilicate toachieve sorption of the polymer between adjacent spaced layers of thephyllosilicate to expand the spacing between a predominance of theadjacent phyllosilicate platelets to at least about 10 Å, when measuredafter sorption of the water-soluble polymer, without first reacting thephyllosilicate with a silane compound or onium ion compound.
 2. Anintercalate in accordance with claim 1, wherein the water is present insaid mixture in an amount in the range of about 20% to about 50% byweight, based on the dry weight of the phyllosilicate in the mixture. 3.An intercalate in accordance with claim 2, wherein the water is presentin the mixture in an amount in the range of about 30% by weight to about45% by weight, based on the dry weight of the phyllosilicate in themixture.
 4. An intercalate in accordance with claim 3, wherein the wateris present in the mixture in an amount in the range of about 35% byweight to about 8% by weight, based on the dry weight of thephyllosilicate in the mixture.
 5. An intercalate in accordance withclaim 1, wherein the concentration of intercalant polymer in saidmixture is at least about 30% by weight, based on the dry weight of thephyllosilicate in the mixture.
 6. An intercalate in accordance withclaim 1, wherein the concentration of intercalant polymer in saidmixture is in the range of about 15% to about 100% by weight, based onthe dry weight of the phyllosilicate in the mixture.
 7. An intercalatein accordance with claim 5, wherein the concentration of intercalantpolymer in said mixture is in the range of about 16% to about 70% byweight, based on the dry weight of the phyllosilicate in the mixture. 8.An intercalate in accordance with claim 7, wherein the concentration ofintercalant polymer in the mixture is in the range of about 16% to lessthan about 35% by weight, based on the dry weight of the phyllosilicatein the mixture.
 9. An intercalate in accordance with claim 6, whereinthe concentration of intercalant polymer in the mixture is in the rangeof about 35% to less than about 55% by weight, based on the dry weightof the phyllosilicate in the mixture.
 10. An intercalate in accordancewith claim 7, wherein the concentration of the intercalant polymer inthe mixture is in the range of about 55% to less than about 70% byweight, based on the dry weight of the phyllosilicate in the mixture.11. An intercalate in accordance with claim 1, wherein the intercalantpolymer is selected from the group consisting of polyvinylpyrrolidone;polyvinyl alcohol; a polymer of a terephthalic acid salt; a hydroxylatedpolymer of a terephthalic acid salt; a polymer of an alkylatedterephthalic acid salt; and polyvinylimine.
 12. An intercalate inaccordance with claim 11, wherein the intercalant polymer has a weightaverage molecular weight in the range of about 225 to about 1,000,000.13. An intercalate in accordance with claim 12, wherein the intercalantpolymer has a weight average molecular weight in the range of about 225to about 50,000.
 14. An intercalate in accordance with claim 13, whereinthe intercalant polymer is polyvinylpyrrolidone.
 15. An intercalate inaccordance with claim 11, wherein the intercalant polymer is selectedfrom the group consisting of polyethylene terephthalate; polybutyleneterephthalate; a polymer polymerized from a monomer selected from thegroup consisting of dihydroxyethyl terephthalate; dihydroxybutylterephthalate; hydroxyethylmethyl terephthalate; hydroxybutylmethylterephthalate; and mixtures thereof.
 16. A method of manufacturing anintercalated phyllosilicate, capable of being exfoliated into individualphyllosilicate platelets, said phyllosilicate having a polymerintercalated between adjacent phyllosilicate plateletscomprising:extruding a mixture of a phyllosilicate; an intercalantpolymer having a functionality selected from the group consisting of anaromatic ring; carbonyl; carboxyl; hydroxyl; amine; amide; ether andester structures; and an aqueous liquid carrier through a die-opening,water being included in the mixture in an amount of at least about 20%by weight, based on the dry weight of the phyllosilicate, and saidpolymer present in the mixture in an amount of 16% to about 80% byweight, based on the dry weight of phyllosilicate to achieveintercalation of said polymer between said adjacent phyllosilicateplatelets in an amount sufficient to space said adjacent phyllosilicateplatelets to a distance of at least about 10 Å without first reactingthe phyllosilicate with a silane compound or onium ion compound.
 17. Themethod of claim 16, wherein the carrier is present in said mixture in anamount of about 20% to about 50% by weight, based on the dry weight ofphyllosilicate in said mixture, when said mixture is extruded.
 18. Themethod of claim 17, wherein said carrier is present in said mixture inan amount of about 30% to about 45% by weight, based on the dry weightof the phyllosilicate in said mixture.
 19. The method of claim 18,wherein the carrier is water and said water is present in the mixture inan amount of about 35% to about 38% by weight, based on the dry weightof the phyllosilicate in the mixture.
 20. The method of claim 18,wherein the concentration of intercalant polymer in said mixture is atleast about 30% by weight, based on the dry weight of the phyllosilicatein the mixture.
 21. The method of claim 20, wherein the concentration ofintercalant polymer in said mixture is in the range of about 15% toabout 100% by weight, based on the dry weight of the phyllosilicate inthe mixture.
 22. The method of claim 21, wherein the concentration ofintercalant polymer in said mixture is in the range of about 16% toabout 70% by weight, based on the dry weight of the phyllosilicate inthe mixture.
 23. The method of claim 22, wherein the concentration ofintercalant polymer in the mixture is in the range of about 16% to lessthan about 35% by weight, based on the dry weight of the phyllosilicatein the mixture.
 24. The method of claim 22, wherein the concentration ofintercalant polymer in the mixture is in the range of about 35% to lessthan about 55% by weight, based on the dry weight of the phyllosilicatein the mixture.
 25. The method of claim 22, wherein the concentration ofthe intercalant polymer in the mixture is in the range of about 55% toless than about 70% by weight, based on the dry weight of thephyllosilicate in the mixture.
 26. The method of claim 16, wherein theintercalant polymer is selected from the group consisting ofpolyvinylpyrrolidone; polyvinyl alcohol; a polymer of terephthalic acidor its salts; and polyvinylimine.
 27. The method of claim 26, whereinthe intercalant polymer has a weight average molecular weight in therange of about 225 to about 1,000,000.
 28. The method of claim 27,wherein the intercalant polymer has a weight average molecular weight inthe range of about 225 to about 10,000.
 29. The method of claim 28,wherein the intercalant polymer is selected from the group consisting ofpolyethylene terephthalate, polybutylene terephthalate, and mixturesthereof.
 30. A composite material comprising a matrix polymer in anamount of about 40% to about 99.95% by weight of the composite material,and about 0.05% to about 60% by weight exfoliated platelets of aphyllosilicate material, said platelets derived from an intercalateformed by extruding a mixture of a phyllosilicate, an intercalantpolymer having a functionality selected from the group consisting of anaromatic ring; carbonyl; carboxyl; hydroxyl; amine; amide; ether andester structures, and an aqueous carrier, said aqueous carrier presentin the mixture in an amount in the range of about 20% by weight to about50% by weight, based on the dry weight of the phyllosilicate in themixture and containing water in an amount of at least about 10% byweight, based on the dry weight of the phyllosilicate, said polymerpresent in an amount of at least about 16% by weight, based on the dryweight of phyllosilicate in the mixture, when the mixture is extruded,to achieve sorption of the intercalant polymer between adjacent spacedlayers of the phyllosilicate to expand the spacing between apredominance of the adjacent phyllosilicate platelets to at least about10 Å, when measured after sorption of the water-soluble polymer withoutfirst reacting the phyllosilicate with a silane compound or onium ioncompound.
 31. A composite material in accordance with claim 30, whereinthe concentration of intercalant polymer in saidphyllosilicate-containing mixture is at least about 10% by weight, basedon the dry weight of the phyllosilicate.
 32. A composite material inaccordance with claim 33, wherein the concentration of intercalantpolymer in said phyllosilicate-containing mixture is at least about 15%by weight, based on the dry weight of the phyllosilicate.
 33. Acomposite material in accordance with claim 30, wherein theconcentration of intercalant polymer in said phyllosilicate-containingmixture is at least about 20% by weight, based on the dry weight of thephyllosilicate.
 34. A composite material in accordance with claim 33,wherein the concentration of intercalant polymer in saidphyllosilicate-containing mixture is at least about 30% by weight, basedon the dry weight of the phyllosilicate.
 35. A composite material inaccordance with claim 34, wherein the concentration of intercalantpolymer in said phyllosilicate-containing mixture is in the range ofabout 50% to about 80% by weight, based on the dry weight of thephyllosilicate.
 36. A composite material in accordance with claim 34,wherein the concentration of intercalant polymer in saidphyllosilicate-containing mixture is in the range of about 50% to about100% by weight, based on the dry weight of the phyllosilicate.
 37. Acomposite material in accordance with claim 30, wherein theconcentration of intercalant polymer in the phyllosilicate-containingmixture is at least about 16% by weight, based on the dry weight of thephyllosilicate.
 38. A composite material in accordance with claim 37,wherein the concentration of intercalant polymer in thephyllosilicate-containing mixture is in the range of about 16% to about70% by weight, based on the dry weight of the phyllosilicate.
 39. Acomposite material in accordance with claim 38, wherein theconcentration of intercalant polymer in the phyllosilicate-containingmixture is in the range of about 16% to less than about 35% by weight,based on the dry weight of the phyllosilicate.
 40. A composite materialin accordance with claim 38, wherein the concentration of intercalantpolymer in the phyllosilicate-containing mixture is in the range ofabout 35% to less than about 55% by weight, based on the dry weight ofthe phyllosilicate.
 41. A composite material in accordance with claim38, wherein the concentration of the intercalant polymer in thephyllosilicate-containing mixture is in the range of about 55% to lessthan about 70% by weight, based on the dry weight of the phyllosilicate.42. A composite material in accordance with claim 30, wherein theintercalant polymer is selected from the group consisting ofpolyvinylpyrrolidone; polyethylene terephthalate; polybutyleneterephthalate; a polymer polymerized from a monomer selected from thegroup consisting of dihydroxyethyl terephthalate; dihydroxybutylterephthalate; hydroxyethylmethyl terephthalate; hydroxybutylmethylterephthalate; and mixtures thereof.
 43. A composite material inaccordance with claim 42, wherein the intercalant polymer has a weightaverage molecular weight in the range of about 225 to about 10,000. 44.A composite material in accordance with claim 43, wherein theintercalant polymer is polyvinylpyrrolidone.
 45. A composite material inaccordance with claim 30, wherein the matrix polymer is selected fromthe group consisting of a polyamide; polyvinyl alcohol; polyethyleneterephthalate; polybutylene terephthalate; polyvinylimine; a polymerpolymerized from a monomer selected from the group consisting ofdihydroxyethyl terephthalate; dihydroxybutyl terephthalate;hydroxyethylmethyl terephthalate; hydroxybutylmethyl terephthalate; andmixtures thereof.
 46. A method of manufacturing a composite materialcontaining about 40% to about 99.95% by weight of a thermoplastic orthermosetting matrix polymer, and about 0.05% to about 60% by weight ofexfoliated platelets of a phyllosilicate material, said plateletsderived from an intercalated phyllosilicate having a polymerintercalated between adjacent phyllosilicate platelets comprising:mixinga phyllosilicate with an intercalant polymer having a functionalityselected from the group consisting of an aromatic ring; carbonyl;carboxyl; hydroxyl; amine; amide; ether and ester structures and water,comprising at least about 20% by weight water and at least about 16% byweight intercalant polymer, based on the dry weight of thephyllosilicate, and extruding the mixture, to achieve intercalation ofsaid polymer between said adjacent phyllosilicate platelets in an amountsufficient to space said adjacent phyllosilicate platelets to a distanceof at least about 10 Å without first reacting the phyllosilicate with asilane compound or onium ion compound; combining the intercalatedplatelets with said matrix polymer, and heating the matrix polymersufficiently to provide for flow of said matrix polymer and exfoliationof said intercalated platelets; and dispersing said exfoliated plateletsthroughout said matrix polymer.
 47. The method of claim 46, wherein saidphyllosilicate, intercalant polymer and water mixture includes adissolved polymer carrier comprising about 5% to about 100% by weightwater, based on the total weight of said phyllosilicate in said mixture.